1. Technical Field
This invention relates to packet switching (or cell switching), in particular methods for allocating requests for switching from one of the inputs of a packet switch to one of the outputs of the packet switch and methods of fabric allocation within a packer switch.
2. Related Art
Input-buffered cell switches and packet routers are potentially the highest possible bandwidth switches for any given fabric and memory technologies, but such devices require scheduling algorithms to resolve input and output contentions. Two approaches to packet or cell scheduling exist (see, for example, A Hung et al, “ATM input-buffered switches with the guaranteed-rate property,” and A Hung et al, Proc. IEEE ISCC '98, Athens, July 1998, pp 331-335). The first approach applies at the connection-level, where bandwidth guarantees are required. A suitable algorithm must satisfy two conditions for this; firstly it must ensure no overbooking for all of the input ports and the output ports, and secondly the fabric arbitration problem must be solved by allocating all the requests for time slots in the frame.